1. A number of different Universal rules were produced by
Unique. The images here cover the Universal, Universal I and the Universal II.
2. The rules used plastic covered paper scales. This method was cheap to produce and
flexible. In the case of the Universal, the plastic has curled slightly and reflected the
light more strongly giving the impression of a white streak along the rule in the image
below.
3. Despite the similarity of names, there were differences in scale layout and marking.
The scales on the Universal and the Universal I are the same but on the Universal they are
un-marked. Both the Universal I and the Universal II had LL1, LL2, A, B, C, and D scales.
The Universal I has sin and tan scales on the stock and a CI (reciprocal scale) on the
slide. The Universal II has no reciprocal scale and its sin and tan scales are on the
slide.
4. There was also a difference in the tables of values on the back. On the Universal the
were mainly properties of metal: on the Universal I they were mainly physical constants;
on the Universal II they were trigonometric formulae.
5. The Universal has a metal and plastic cursor which was used on earlier models.
Universal I: LU (=LL1), S, A [B, R (=CI), C] D, T, LL (=LL3)
Universal II: (=LL1), A [B, S, T, C] D, (=LL3)
Universal I and Universal II: Plastic with white plastic frame top and bottom